搜题请搜索小程序“爱下问搜题”
问题 选择题

图5—19表示某些工业部门对区位因素（仅考虑原料、能源、劳动力）的依赖程度，判断图中①、②、③代表的工业部门分别可能是（   ）

图5—19

①炼铝、服装、家具制造 ②炼铝、制糖、服装 ③汽车、造船、水泥 ④炼铜、奶制品、制鞋

A．①④

B．②④

C．②③

D．①③

答案

B

此题的关键是会读三角坐标图。图中每一个点在三个数轴上都有相应的数值，三轴都是有方向的，读图时应该读取与该数轴成锐角时的数值

单项选择题

选择设计地面连接形式，要综合考虑各种因素，一般情况下自然地形坡度大于8%时，应采用( )连接形式。

A．斜坡式
B．平坡式
C．台阶式
D．混合式
查看答案
单项选择题

In fall 2006, the National Basketball Association (NBA) started using basketballs made with synthetic, or man-made, material instead of leather. They made the change because they wanted every basketball they use to feel and bounce the same. Not all leather balls are exactly alike in weight or how they bounce, but the synthetic balls are.
However, some players complained right away that the new balls bounced differently and were actually harder to control than the leather ones.
Physics helped answer questions about why the new balls felt different. For example, the scientists studied friction, which in this case affects the ability of a player to hold onto a ball. "The greater the friction, the better it will stick to his hand," explains a scientist.
Tests on both wet and dry balls showed that while the synthetic ball was easier to hold onto when dry, it had less friction and became much harder to hold onto when wet. That’s because sweat stays on the surface of the synthetic balls but gets taken into the leather balls.
The scientists also tested bounce and found that the logo printed on the new balls made their surface uneven and caused them to bounce a little strangely compared with the leather balls.
In January, the NBA went back to using the leather balls. They aren’t perfect, but for now, that’s just the way the ball bounces.

The ball is easier to hold on to ______.

A．when friction is greater

B．when friction is less

C．when it is heavier

D．when it bounces strangely
查看答案